This invention relates to an enantiopure (S)-enantiomer of a compound known to exist as a racemate, its use as a pharmaceutical, in particular in the treatment of neurodegenerative disorders, a process for its production, and pharmaceutical formulations including the enantiomer.
A major problem with existing drugs used to treat neurodegenerative disorders is a lack of predictability in the concentration of a drug in a patient's blood plasma resulting from administration of a given quantity of that drug, i.e. existing drugs do not exhibit linear pharmacokinetics. It has been stated that an ideal drug in this field would show a linear relationship between blood plasma concentration and dose size so that a given change in dose would yield a predictable change in blood plasma concentration of the drug [`Pharmacokinetics of old, new and yet-to-be discovered antiepileptic drugs`, R H Levy and B M Kerr, Epilepsia, vol 30, Supp 1, S35-S41, 1989].
Parent application Ser. No. 07/915,489 discloses compounds for use in the treatment of neurodegenerative disorders, having the formula ##STR1## wherein Ar.sub.1 and Ar.sub.2, which may be the same or different, independently represent phenyl substituted by one or more of amino, nitro, chlorine, bromine, hydroxy, C1 to 6 alkoxy, C1 to 6 alkyl or cyano; in addition one of Ar.sub.1 or Ar.sub.2 may also represent phenyl;
R.sub.1 represents hydrogen or C1 to 6 alkyl; PA1 R.sub.2 represents hydrogen or COCH.sub.2 NH.sub.2 ; PA1 R.sub.3 represents hydrogen or C1 to 6 alkyl; provided that when R.sub.2 represents hydrogen, then one or both of Ar.sub.1 and Ar.sub.2 may also represent phenyl, fluorophenyl or 2-, 3- or 4-pyridinyl and R.sub.1 may also represent C1 to 6 alkoxycarbonyl or trifluoromethyl; or a pharmaceutically acceptable salt thereof.
Included in these compounds is .alpha.-phenyl-2-pyridineethanamine [referred to therein as 1-phenyl-2-(2-pyridinyl)ethylamine], ##STR2##